1 // Code to access multiple segments within gcc.
3 // Copyright (C) 2008 Kevin O'Connor <kevin@koconnor.net>
5 // This file may be distributed under the terms of the GNU GPLv3 license.
9 #include "ioport.h" // insb
11 // Dummy definitions used to make sure gcc understands dependencies
12 // between SET_SEG and GET/READ/WRITE_SEG macros.
13 extern u16 __segment_ES, __segment_CS, __segment_DS, __segment_SS;
15 // Low level macros for reading/writing memory via a segment selector.
16 #define READ8_SEG(SEG, var) ({ \
17 typeof(var) __value; \
18 __asm__("movb %%" #SEG ":%1, %b0" : "=Qi"(__value) \
19 : "m"(var), "m"(__segment_ ## SEG)); \
21 #define READ16_SEG(SEG, var) ({ \
22 typeof(var) __value; \
23 __asm__("movw %%" #SEG ":%1, %w0" : "=ri"(__value) \
24 : "m"(var), "m"(__segment_ ## SEG)); \
26 #define READ32_SEG(SEG, var) ({ \
27 typeof(var) __value; \
28 __asm__("movl %%" #SEG ":%1, %0" : "=ri"(__value) \
29 : "m"(var), "m"(__segment_ ## SEG)); \
31 #define WRITE8_SEG(SEG, var, value) \
32 __asm__("movb %b0, %%" #SEG ":%1" : \
33 : "Q"(value), "m"(var), "m"(__segment_ ## SEG))
34 #define WRITE16_SEG(SEG, var, value) \
35 __asm__("movw %w0, %%" #SEG ":%1" : \
36 : "r"(value), "m"(var), "m"(__segment_ ## SEG))
37 #define WRITE32_SEG(SEG, var, value) \
38 __asm__("movl %0, %%" #SEG ":%1" : \
39 : "r"(value), "m"(var), "m"(__segment_ ## SEG))
41 // Low level macros for getting/setting a segment register.
42 #define __SET_SEG(SEG, value) \
43 __asm__("movw %w1, %%" #SEG : "=m"(__segment_ ## SEG) \
45 #define __GET_SEG(SEG) ({ \
47 __asm__("movw %%" #SEG ", %w0" : "=r"(__seg) \
48 : "m"(__segment_ ## SEG)); \
51 // Macros for automatically choosing the appropriate memory size
53 extern void __force_link_error__unknown_type();
55 #define __GET_VAR(seg, var) ({ \
57 if (__builtin_types_compatible_p(typeof(__val), u8) \
58 || __builtin_types_compatible_p(typeof(__val), s8)) \
59 __val = READ8_SEG(seg, var); \
60 else if (__builtin_types_compatible_p(typeof(__val), u16) \
61 || __builtin_types_compatible_p(typeof(__val), s16)) \
62 __val = READ16_SEG(seg, var); \
63 else if (__builtin_types_compatible_p(typeof(__val), u32) \
64 || __builtin_types_compatible_p(typeof(__val), s32)) \
65 __val = READ32_SEG(seg, var); \
67 __force_link_error__unknown_type(); \
70 #define __SET_VAR(seg, var, val) do { \
71 if (__builtin_types_compatible_p(typeof(var), u8) \
72 || __builtin_types_compatible_p(typeof(var), s8)) \
73 WRITE8_SEG(seg, var, (val)); \
74 else if (__builtin_types_compatible_p(typeof(var), u16) \
75 || __builtin_types_compatible_p(typeof(var), s16)) \
76 WRITE16_SEG(seg, var, (val)); \
77 else if (__builtin_types_compatible_p(typeof(var), u32) \
78 || __builtin_types_compatible_p(typeof(var), s32)) \
79 WRITE32_SEG(seg, var, (val)); \
81 __force_link_error__unknown_type(); \
84 // Macros for accessing a variable in another segment. (They
85 // automatically update the %es segment and then make the appropriate
87 #define __GET_FARVAR(seg, var) ({ \
89 GET_VAR(ES, (var)); })
90 #define __SET_FARVAR(seg, var, val) do { \
91 typeof(var) __sfv_val = (val); \
93 SET_VAR(ES, (var), __sfv_val); \
96 // Macros for accesssing a 32bit pointer from 16bit mode. (They
97 // automatically update the %es segment, break the pointer into
98 // segment/offset, and then make the access.)
99 #define __GET_FARPTR(ptr) ({ \
100 typeof(&(ptr)) __ptr = &(ptr); \
101 GET_FARVAR(FARPTR_TO_SEG(__ptr) \
102 , *(typeof(__ptr))FARPTR_TO_OFFSET(__ptr)); })
103 #define __SET_FARPTR(ptr, val) do { \
104 typeof (&(ptr)) __ptr = &(ptr); \
105 SET_FARVAR(FARPTR_TO_SEG(__ptr) \
106 , *(typeof(__ptr))FARPTR_TO_OFFSET(__ptr) \
110 // Macros for converting to/from 32bit style pointers to their
111 // equivalent 16bit segment/offset values.
112 #define FARPTR_TO_SEG(p) (((u32)(p)) >> 4)
113 #define FARPTR_TO_OFFSET(p) (((u32)(p)) & 0xf)
114 #define MAKE_FARPTR(seg,off) ((void*)(((seg)<<4)+(off)))
119 // Definitions when in 16 bit mode.
120 #define GET_FARVAR(seg, var) __GET_FARVAR((seg), (var))
121 #define SET_FARVAR(seg, var, val) __SET_FARVAR((seg), (var), (val))
122 #define GET_VAR(seg, var) __GET_VAR(seg, (var))
123 #define SET_VAR(seg, var, val) __SET_VAR(seg, (var), (val))
124 #define SET_SEG(SEG, value) __SET_SEG(SEG, (value))
125 #define GET_SEG(SEG) __GET_SEG(SEG)
126 #define GET_FARPTR(ptr) __GET_FARPTR(ptr)
127 #define SET_FARPTR(ptr, val) __SET_FARPTR((ptr), (val))
129 static inline void insb_far(u16 port, void *farptr, u16 count) {
130 SET_SEG(ES, FARPTR_TO_SEG(farptr));
131 insb(port, (u8*)FARPTR_TO_OFFSET(farptr), count);
133 static inline void insw_far(u16 port, void *farptr, u16 count) {
134 SET_SEG(ES, FARPTR_TO_SEG(farptr));
135 insw(port, (u16*)FARPTR_TO_OFFSET(farptr), count);
137 static inline void insl_far(u16 port, void *farptr, u16 count) {
138 SET_SEG(ES, FARPTR_TO_SEG(farptr));
139 insl(port, (u32*)FARPTR_TO_OFFSET(farptr), count);
141 static inline void outsb_far(u16 port, void *farptr, u16 count) {
142 SET_SEG(ES, FARPTR_TO_SEG(farptr));
143 outsb(port, (u8*)FARPTR_TO_OFFSET(farptr), count);
145 static inline void outsw_far(u16 port, void *farptr, u16 count) {
146 SET_SEG(ES, FARPTR_TO_SEG(farptr));
147 outsw(port, (u16*)FARPTR_TO_OFFSET(farptr), count);
149 static inline void outsl_far(u16 port, void *farptr, u16 count) {
150 SET_SEG(ES, FARPTR_TO_SEG(farptr));
151 outsl(port, (u32*)FARPTR_TO_OFFSET(farptr), count);
156 // In 32-bit mode there is no need to mess with the segments.
157 #define GET_FARVAR(seg, var) \
158 (*((typeof(&(var)))MAKE_FARPTR((seg), (u32)&(var))))
159 #define SET_FARVAR(seg, var, val) \
160 do { GET_FARVAR((seg), (var)) = (val); } while (0)
161 #define GET_VAR(seg, var) (var)
162 #define SET_VAR(seg, var, val) do { (var) = (val); } while (0)
163 #define SET_SEG(SEG, value) ((void)(value))
164 #define GET_SEG(SEG) 0
165 #define GET_FARPTR(ptr) (ptr)
166 #define SET_FARPTR(ptr, val) do { (ptr) = (val); } while (0)
168 #define insb_far(port, farptr, count) insb(port, farptr, count)
169 #define insw_far(port, farptr, count) insw(port, farptr, count)
170 #define insl_far(port, farptr, count) insl(port, farptr, count)
171 #define outsb_far(port, farptr, count) outsb(port, farptr, count)
172 #define outsw_far(port, farptr, count) outsw(port, farptr, count)
173 #define outsl_far(port, farptr, count) outsl(port, farptr, count)